820
FXUS65 KBYZ 272303
AFDBYZ
AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE BILLINGS MT
503 PM MDT SUN SEP 27 2026
KEY MESSAGES
- ISOLATED SHOWERS AND A FEW STRONG THUNDERSTORMS ARE POSSIBLE
THIS EVENING AND OVERNIGHT. BEST CHANCE FOR PRECIPITATION WILL
BE OVER THE BEARTOOTH/ABSAROKA MOUNTAINS AND SE MONTANA.
- MILD AND DRY PATTERN PREVAILS TUESDAY INTO NEXT WEEKEND.
DISCUSSION
TODAY THROUGH SATURDAY...
CURRENT UPPER LEVEL PATTERN SHOWS SOUTHWEST FLOW WITH TROUGHING
OVER THE WEST COAST. MULTIPLE ROUNDS OF ENERGY WILL WORK THEIR WAY
THROUGH THE REGION AS TROUGHING MOVES SOUTH AND EAST.
PRECIPITATION AMOUNTS CONTINUE THE DOWNWARD TREND FOR THIS EVENING
AND OVERNIGHT. AREAS ALONG THE MT/DAKOTAS BORDER HAVE ABOUT A
20-40% CHANCE FOR AT LEAST A QUARTER INCH OF PRECIPITATION, WITH
THE BEARTOOTH/ABSAROKAS HAVING SIMILAR CHANCES FOR A HALF AN
INCH SUNDAY NIGHT INTO MONDAY. WITH PRECIPITABLE WATER VALUES
CONTINUING TO BE ELEVATED ACROSS SE MT, LOCALLY HIGHER RAINFALL
AMOUNTS ARE POSSIBLE WITH ANY STRONGER THUNDERSTORMS THAT FORM.
ONE LIMITING FACTOR FOR THUNDERSTORM DEVELOPMENT CONTINUES TO BE A
CAP/INVERSION IN MODEL SOUNDINGS FOR THIS AREA. HI-RES ENSEMBLES
AND MODELS CONTINUE TO SHOW MUCAPE VALUES OF 500-1000 J/KG AND
35-45 KTS OF BULK SHEAR. IF STORMS ARE ABLE TO TAP INTO THE ENERGY
AVAILABLE, HEAVY RAIN, SMALL HAIL AND GUSTY WINDS ARE LIKELY. THE
BEST TIMEFRAME FOR STORMS THIS EVENING AND OVERNIGHT LOOKS TO BE
9PM-6AM MDT MONDAY MORNING. THERE IS THEN ABOUT A 20% CHANCE FOR
LOW STRATUS/FOG TO DEVELOP MONDAY MORNING FOR SE MT AS WELL.
ADDITIONAL SCATTERED SHOWERS AND ISOLATED THUNDERSTORMS ARE
POSSIBLE INTO MONDAY AFTERNOON MAINLY ACROSS THE HIGHER TERRAIN
AND SOUTHEAST MT. LOW CLOUDS MAY LIMIT THUNDERSTORM DEVELOPMENT AS
DRYER AIR AND CLEARING DOES NOT MOVE IN UNTIL THE EVENING. TIMING
FOR POTENTIAL THUNDERSTORMS MONDAY LOOKS TO BE MAINLY DURING THE
AFTERNOON HOURS. DRYER AIR MOVES IN TUESDAY AS WEST TO NORTHWEST
FLOW MOVES IN AND PERSISTS THROUGH THE WEEK. HIGH TEMPERATURES
WILL REMAIN SEASONABLE IN THE 60S TO LOW 70S, WITH TUESDAY
TRENDING WARMER IN THE UPPER 70S. TS
AVIATION
00Z TAF/AVIATION DISCUSSION...UPPER LEVEL SYSTEM OVER THE AREA
TONIGHT THROUGH TOMORROW WILL PRODUCE ISOLATED TO SCATTERED
SHOWERS AND A FEW EMBEDDED THUNDERSTORMS. THERE IS A CONDITIONAL
THREAT FOR A FEW STRONG THUNDERSTORMS LATE THIS EVENING INTO
TOMORROW MORNING FROM ROSEBUD COUNTY EAST INTO THE DAKOTAS AND NE
WYOMING. STRATUS AND LOCALIZED FOG ARE A POSSIBILITY OVER SE
MONTANA AFTER ABOUT 09Z LASTING INTO THE LATE MORNING HOURS
MONDAY, WITH MVFR TO IFR FLIGHT CATEGORIES POSSIBLE INCLUDING
KMLS/KBHK/K4BQ. WINDS WILL BECOME LIGHT OVERNIGHT AT THE SURFACE,
BUT NEAR SHOWERS/THUNDESTORMS GUSTS 20 TO 30KTS ARE POSSIBLE.
CHAMBERS
PRELIMINARY POINT TEMP/POPS
TDY MON TUE WED THU FRI SAT
-------------------------------------------------------
BIL 064 046/070 046/077 051/071 044/067 045/073 049/067
2/W 22/W 10/U 00/U 00/U 00/U 11/B
LVM 062 038/070 039/075 044/071 038/070 041/075 044/069
0/E 22/T 10/U 00/U 00/U 00/U 11/U
HDN 068 045/070 043/078 047/071 042/069 042/074 046/068
2/W 22/W 00/U 00/U 00/U 00/U 11/B
MLS 067 052/070 046/077 050/069 043/065 045/071 048/067
2/W 22/W 10/U 00/U 01/U 00/U 11/B
4BQ 069 054/071 048/077 050/070 045/066 046/073 049/068
0/B 42/W 20/U 00/U 01/U 00/U 10/B
BHK 069 049/071 046/077 048/070 040/064 041/071 044/067
2/W 62/T 20/U 00/U 01/U 00/U 01/B
SHR 067 046/067 042/075 043/070 040/067 040/073 045/068
0/B 23/W 10/U 00/U 11/U 00/U 11/B
BYZ WATCHES/WARNINGS/ADVISORIES
MT...NONE.
WY...NONE.
WEATHER.GOV/BILLINGS
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